It will be Rectangle – that is simplest way.
To handle all object I should create a Map – it will be managed from our Scene (defined in p.4).

Map radarObjectsMap = new HashMap();

Dots will be draw on rectangle but first I must find a way to transform space points to radar points.
To calculate x position of the object I get it is X position in the space and devide it by space width – this is my percentage of the space where object is paced, so this is also percentage of position on radar.
It is very simple and can be done like this:

Pos is special class that contains only fields: x,y, width and height.

I must add methods to handle adding, removing and moving objects on the radar.
I will just use Map. In adding I will define size of the object, first position and color. to define position I will use my method from above. Also I will check if Map already contains this object:

4)
To define scene I will extends Scene from AndEngie API and in each attachChild and removeChild I will call Radar methods to add and remove objects. Finally I define UpdateHandler to manage object movement.

Most of sprites in games has states that will change after fires some event.

Simple example:
We have one sprite “Dot”. This sprite has 3 states. Sprite can be clicked, when it will change state. Every state has different texture.

SHOW_EMPTY – empty Dot, sprite will not change it state
SHOW_SELECTED – Dot will be filled, sprite will not change it state
DRAW_EMPTY – Empty dot to change, sprite will change state to DRAW_SELECTED
DRAW_SELECTED- Filled Dot to change, sprite will change state to DRAW_EMPTY

BAD SOLUTION
We will use “if … else” statement and some methods and fields to handle states.